Crankcase Sludge Trap

onMay 28, 2012

The trap in the crankshaft is hard to remove but is a must do whenever the bottom end is apart. I learnt this lesson as a youngster when I rebuilt my 500 Trophy in a corrugated iron lean to at the back of the commune (yeah alright, bloody hippies, but this was in the very early 70’s and I was not the only TOMCC member who lived there, let’s just give him a nick name, say Micky Rat, to protect his identity). I couldn’t undo the screw cap, they’re bloody tight, and thought what harm can it do if it’s that hard to get off it should be okay. Big ends seized when I opened her up on the way back from Whatawhata.

Follow the handbook to remove the cap. When that doesn’t work try heating the crankshaft up and try again. The last resort is to use a hammer and cold chisel on the slot to free it up.

Now for the clever bit – remove the flywheel bolt that retains the trap tube, take your Shadbolt extractor, see photo, and insert it in the trap until you can see the hole in the threaded shaft. Now drop the pin down the bolt hole, Shaddy uses one of those Allen keys with a handle and holds a magnet against the shaft to hold the pin while lowering it down the bolt hole. When the pin locates in the hole in the threaded bar he removes the magnet and withdraws the Allen key. Now wind up the nut drawing the trap tube out of the crankshaft. Simple eh? I had a grader wheel stud from the days when my Dad worked down the Oto County that I could jam up the tube and sweat it out but this tool makes it easy. When you reassemble the crank British Spares can supply an Allen head cap that is apparently easier to remove.